Let us hope this doesn't happen, even if the internet could cope with the massive increase in bandwidth required to supply all T.V. (which I doubt), how many Gigabytes per month do you think users would be downloading over their broadband connections and how much would a truly un-capped broadband service cost?
Philosophically I'm in favour of not cluttering up the airwaves for communication which is (essentially) fixed-point to fixed-point, but that means a dedicated cable system (like USA) rather than competing for bandwidth on the wirewaves instead.
In time, ISPs will get source-specific multicast implemented properly down to end devices. Probably about the same time a IPv6 is widely deployed since that generally removes address translation along the way.